We performed this study to evaluate the clinical and radiological results of metal on metal articulation change for the treatment of ceramic liner or head fractures in total hip arthroplasty (THA). We retrospectively reviewed 8 patients with revision THA using liner cementation (metal on metal) due to ceramic fracture (liner fracture; 5 cases, head fracture; 3 cases). They were followed up for an average of 30 months (range 12 to 68 months). At the surgery, we removed ceramic liner and head, the joint cavity was irrigated with saline to remove remnants of ceramic particles. After that, the inner surface of the metal shell was roughened with a high-speed diamond burr to improve the fixation strength of the liner. Metal inlay polyethylene (Metasul®, Centerpulse Orthopedics, Austin, TX) liner was used and the back surface of the liner was routinely down sized and roughened like spider web with an electrical burr to ensure stable fixation with bone cement. We evaluated clinical result using Harris Hip Score (HSS) and the Western Ontario and McMaster Universities Osteoarthritis index (WOMAC) score and radiological evaluation was done using the mothod of DeLee and Charnley for the acetabular osteolysis and method of Gruen et al. for the femoral osteolysis. The mean Harris hip scores improved from 65.3 pre-operatively to 93.8 at the final follow-up. There were no changes in cup position, no progression of osteolytic lesion around the femoral and acetabular components and no measurable wear of metal on metal bearing articulation at the last follow-up radiographs. There was one case of recurrent dislocation after surgery and the patient treated with greater trochanter distal advancement. This study showed that for the treatment of ceramic liner or head fractures, after thorough removal of ceramic particles, cementation into a metal shell and changing the articulation to metal-on-metal provided good clinical and radiological results.
The aim of the present study was to report the midterm follow up results of second generation metal-on-metal cementless total hip arthroplasties in patients younger than 50 years. From December 1997 and January 2003, 91 metal-on-metal cementless primary total arthroplasties in 77 patients (who were younger than 50 years) were performed in our institution. Among them 72 hips in 63 patients could be followed more than 5 years. There were 18 women (22 hips) and 44 men (50 hips) with a mean age at surgery of 39 years (range 22 to 49 years) and a mean follow up of 7 years (range 5 to 10 years). The most common cause of total hip replacement were avascular necrosis of femoral head (37 hips in 28 patients, 51%) and second one was osteoarthritis (13 hips in 13 patients, 18%). We used Fitmore (Zimmer, Winterthur, Switzerland) cup in all cases and used 28mm Metasul femoral head. About the femoral stem, CLS (Protek AG/Zimmer, Bern, Switzerland) stems were used in 48 hips and Cone prosthesis® (Protek AG, Berne, Switzerland) were used in 24 hips. We evaluated clinical result using Harris hip score (HSS) and the Western Ontario and McMaster Universities Osteoarthritis index (WOMAC) score and radiological evaluation was done using the method of DeLee and Charnley for the acetabular osteolysis and method of Gruen et al. for the femoral osteolysis. The mean HSS improved from 58.9 (range 35 to 69) preoperatively to 92.2 (range 82 to 100) postoperatively. The mean WOMAC score improved from 72.2 (range 63 to 94) preoperatively to 29.2 (range 17 to 51) postoperatively. In radiological evaluation, all femoral and acetabular component were well fixed without loosening or subsidence. But osteolysis was observed in 10 (14%) of total 72 hips (Acetabular osteolysis in 5 cases-Zone 2; 2, Zone 3; 3, Femoral osteolysis in 6 cases-Zone 1; 6, Zone 7; 1). About the major complications, there were immediate postoperative deep infection 1 case, delayed infection 1 case and recurrent dislocation 1 case. There was no revision case due to aseptic loosening. The treatment of second generation metal-on-metal cementless total hip arthroplasties in patients younger than 50 years showed favorable midterm results.
